LTC4226 Datasheet, PDF (1/24 Pages) Linear Technology – Wide Operating Range Dual Hot Swap Controller Fast Response Limits Peak Fault Current

Features
n _{Allows Safe Board Insertion into Live Backplane}
n _{Selectable Current Limit and Dual-Rate Timer}
Accommodate Load Surges
n _{Fast Response Limits Peak Fault Current}
n _{Wide Operating Voltage Range: 4.5V to 44V}
n _{Optional Auto-Retry or Latchoff after}
Overcurrent Fault
n _{High Side Drive for External N-Channel MOSFET}
n _{Allows Parallel Power Paths for High Current}
Applications
n _{Available in 16-Pin QFN (3mm × 3mm) and MSOP}
Packages
Applications
n _{Apple FireWire/IEEE 1394}
n _{Disk Drives}
n _{Rugged 12V, 24V Applications}
n _{Hot Board/Connector Insertion}
n _{Uni/Bidirectional Current Limiter/Circuit Breaker}
LTC4226
Wide Operating Range
Dual Hot Swap Controller
Description
The LTC^®4226 dual Hot Swap™ controller allows two
power paths to be safely inserted and removed from a
live backplane or powered connector. Using N-channel
pass transistors, supply voltages ranging from 4.5V to
44V are ramped up at an adjustable rate.
Three selectable ratios of current limit to circuit breaker
threshold accommodate noisy loads and momentary high
peak currents without interruption, while a dual-rate fault
timer protects the MOSFET from extended output over-
current events. FAULT outputs indicate the circuit breaker
status. The LTC4226-1 remains off after a fault while the
LTC4226-2 automatically retries after a 0.5s delay.
The LTC4226 can also be configured as a bidirectional cur-
rent limiter/circuit breaker. For high current applications,
two channels may be configured as parallel power paths.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Hot
Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of
their respective owners.
Typical Application
2 Port FireWire Application
SS3P5
7V TO 33V
CURRENT
LIMIT
SELECT
30mΩ _FDMS86500DC
V_CC1
ON1
FAULT1
CLS
FAULT2
ON2
V_CC2
SENSE1 GATE1
LTC4226-2
SENSE2 GATE2
OUT1
FTMR1
GND
FTMR2
OUT2
SMCJ33A* ^{30mΩ FDMS86500DC}
*36.7V TO 40.6V BV
PORT 1
1394 1394
SOCKET PLUG
220nF
220nF
PORT 2
1394 1394
SOCKET PLUG
4226 TA01a
V_CC
10V/DIV
V_OUT
10V/DIV
Inrush after Load Connection
CABLE INSERTION
I_OUT
1A/DIV
INRUSH
CURRENT
V_CC = 12V
C_LOAD = 1mF
1ms/DIV
4226 TA01b
4226f
1